Arsenic numbers a concern for scientist

Trevor Dummer – an associate professor with UBC’s Faculty of Medicine, an environmental epidemiology PhD and an investigator for the Centre of Excellence in Cancer Prevention – said that if his water source consistently had an arsenic concentration of 0.007 or 0.008 mg/L, he wouldn’t drink it.

His proclamation was made in front of more than 130 people last week at the Drinking Water, Arsenic and Your Health public-information session organized by a group of residents who call themselves the White Rock Arsenic & Manganese Working Group.

The City of White Rock has published 107 of its water-testing results dating back to January 2016 from several locations throughout the city. The metal results show an average arsenic concentration of 0.0074 mg/L.

Of the reported results, 57 samples tested at 0.007 mg/L or above.

However, Health Canada established an arsenic maximum acceptable concentration (MAC) of 0.0100 mg/L, based on municipal and residential-scale treatment achievability. That guideline is enforced by Fraser Health and followed by the City of White Rock.

Dummer, who held Wednesday’s presentation at First United Church free-of-charge, said the intent of the session was to inform the public on the health risks of drinking arsenic-laced water.

“If I was aware that my drinking water was consistently at 0.007 mg/L or 0.008 mg/L, then I would think very strongly about drinking it and would probably move to bottled water,” he said.

Dummer applauded the City of White Rock for posting the results on its website.

“It’s good to be able to see the water-testing results so then you can make an informed opinion on whether you should drink it,” he said.

According to the city’s published arsenic testing results, 10 (9.3 per cent) test samples came in at 0.005 mg/L or less.

In order to have “essentially negligible” health impacts, drinking water should have an arsenic concentration of 0.003 mg/L or less, according to Health Canada drinking-water guidelines. Essentially negligible equates to one new cancer case per 100,000 people. Water with an arsenic concentration of 0.0100 mg/L can have three to 39 new cancer cases per 100,000 people.

Although some of the scientific evidence Dummer researched has been “contested,” it’s his opinion that the maximum acceptable concentration of arsenic should be lowered.

“My own personal opinion as a scientist is that we need to revisit the maximum acceptable concentration of .0100 mg/L and it should be lowered to 0.0050 mg/L. I would also say that I would probably avoid drinking water if the levels from the tap I was drinking from were constantly above seven or eight,” Dummer said, adding that arsenic concentrations can vary from time to time.

He said nearly every jurisdiction in North America follows a 0.010 mg/L MAC, with the exception of New Jersey, which follows a 0.005 mg/L maximum.

“Perhaps getting to below .0005 mg/L is the way forward,” he said.

Dummer also noted it’s important to take the data in context, as the most effective steps to prevent cancer are to eat healthy and not smoke.

Last March, the city received an $11.8-million federal provincial grant for a planned arsenic and manganesetreatment facility. The city is to make up the remainder of the $14,205,000 project.

During the funding announcement, Mayor Wayne Baldwin explained why the arsenic and manganese treatment process is needed, even though Fraser Health and the city say the water is safe to drink.

“The arsenic does occasionally pop up, not from the whole system, but from one or two wells,” Baldwin said. “If it blends with the rest of the water, it’s OK, it’s not an issue. But it does pop up, what it’s saying to us, if it’s coming up now, at some point in the future it could be on a sustained basis and that’s not acceptable.”

Since January 2016, there were a total of six testing results above the 0.010 mg/L MAC at three different sampling locations.